The Biostatistics Core Facility brings together expertise and intellectual resources in biostatistics, clinical trials, epidemiology, statistical computing, and database and information management. The Core Facility has wide involvement in support of Cancer Center research in clinical trials, prevention and cancer control research, genetic and population studies, and translational research. Activities include: 1) protocol development; 2) protocol review; 3) study monitoring; 4) data analysis and reporting; 5) database development and management; 6) applications with large population databases; 7) data services and computer programming; 8) research-related website development; 9) education; and 10) statistical consultation and collaboration. The Core Facility closely supports activities of the Clinical Trials Unit. Biostatisticians are actively involved in review of all protocols as part of the Clinical Trials Development and Review Committee. Recent recruitment of the Core Facility has enhanced the biostatistical support of Cancer Center activities, allowing the fostering of the philosophy that productive research requires high quality biostatistical collaboration. Activities of the Core Facility in support of cancer research are illustrated by work on clinical trial protocol development in developmental therapeutics, data mining (genetic microarray data), genetic epidemiology (such as the Colon Polyp and Colon Cancer Sib Pair Study), behavioral research, development of an interactive Clinical Trials Database, and exploration of large population databases for research on cancer preventive and treatment service delivery. The Core Facility has supported research in each of the Programs in the Cancer Center. Collaboration of Core Facility personnel with Cancer Center investigators on the design, operation, analysis, and interpretation of cancer studies has enhanced the quality of the science.